getopt.py

"""Parser for command line options.

This module helps scripts to parse the command line arguments in
sys.argv. It supports the same conventions as the Unix getopt()
function (including the special meanings of arguments of the form `-'
and `--'). Long options similar to those supported by GNU software
may be used as well via an optional third argument. This module
provides two functions and an exception:

getopt() -- Parse command line options
gnu_getopt() -- Like getopt(), but allow option and non-option arguments
to be intermixed.
GetoptError -- exception (class) raised with 'opt' attribute, which is the
option involved with the exception.
"""

# Long option support added by Lars Wirzenius <liw@iki.fi>.
#
# Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions
# to class-based exceptions.
#
# Peter Åstrand <astrand@lysator.liu.se> added gnu_getopt().
#
# TODO for gnu_getopt():
#
# - GNU getopt_long_only mechanism
# - allow the caller to specify ordering
# - RETURN_IN_ORDER option
# - GNU extension with '-' as first character of option string
# - optional arguments, specified by double colons
# - a option string with a W followed by semicolon should
# treat "-W foo" as "--foo"

__all__= ["GetoptError", "error", "getopt", "gnu_getopt"]

importos

try:
fromgettextimportgettextas_
exceptImportError:
# Bootstrapping Python: gettext's dependencies not built yet
def_(s):
returns


classGetoptError(Exception):
opt=""
msg=""

def__init__(self, msg, opt=""):
self.msg=msg
self.opt=opt
Exception.__init__(self, msg, opt)

def__str__(self):
returnself.msg


error=GetoptError# backward compatibility


defgetopt(args, shortopts, longopts=[]):
"""getopt(args, options[, long_options]) -> opts, args

 Parses command line options and parameter list. args is the
 argument list to be parsed, without the leading reference to the
 running program. Typically, this means "sys.argv[1:]". shortopts
 is the string of option letters that the script wants to
 recognize, with options that require an argument followed by a
 colon (i.e., the same format that Unix getopt() uses). If
 specified, longopts is a list of strings with the names of the
 long options which should be supported. The leading '--'
 characters should not be included in the option name. Options
 which require an argument should be followed by an equal sign
 ('=').

 The return value consists of two elements: the first is a list of
 (option, value) pairs; the second is the list of program arguments
 left after the option list was stripped (this is a trailing slice
 of the first argument). Each option-and-value pair returned has
 the option as its first element, prefixed with a hyphen (e.g.,
 '-x'), and the option argument as its second element, or an empty
 string if the option has no argument. The options occur in the
 list in the same order in which they were found, thus allowing
 multiple occurrences. Long and short options may be mixed.

 """

opts= []
iftype(longopts) ==type(""):
longopts= [longopts]
else:
longopts=list(longopts)
whileargsandargs[0].startswith("-") andargs[0] !="-":
ifargs[0] =="--":
args=args[1:]
break
ifargs[0].startswith("--"):
opts, args=do_longs(opts, args[0][2:], longopts, args[1:])
else:
opts, args=do_shorts(opts, args[0][1:], shortopts, args[1:])

returnopts, args


defgnu_getopt(args, shortopts, longopts=[]):
"""getopt(args, options[, long_options]) -> opts, args

 This function works like getopt(), except that GNU style scanning
 mode is used by default. This means that option and non-option
 arguments may be intermixed. The getopt() function stops
 processing options as soon as a non-option argument is
 encountered.

 If the first character of the option string is `+', or if the
 environment variable POSIXLY_CORRECT is set, then option
 processing stops as soon as a non-option argument is encountered.

 """

opts= []
prog_args= []
ifisinstance(longopts, str):
longopts= [longopts]
else:
longopts=list(longopts)

# Allow options after non-option arguments?
ifshortopts.startswith("+"):
shortopts=shortopts[1:]
all_options_first=True
elifos.environ.get("POSIXLY_CORRECT"):
all_options_first=True
else:
all_options_first=False

whileargs:
ifargs[0] =="--":
prog_args+=args[1:]
break

ifargs[0][:2] =="--":
opts, args=do_longs(opts, args[0][2:], longopts, args[1:])
elifargs[0][:1] =="-"andargs[0] !="-":
opts, args=do_shorts(opts, args[0][1:], shortopts, args[1:])
else:
ifall_options_first:
prog_args+=args
break
else:
prog_args.append(args[0])
args=args[1:]

returnopts, prog_args


defdo_longs(opts, opt, longopts, args):
try:
i=opt.index("=")
exceptValueError:
optarg=None
else:
opt, optarg=opt[:i], opt[i+1 :]

has_arg, opt=long_has_args(opt, longopts)
ifhas_arg:
ifoptargisNone:
ifnotargs:
raiseGetoptError(_("option --%s requires argument") %opt, opt)
optarg, args=args[0], args[1:]
elifoptargisnotNone:
raiseGetoptError(_("option --%s must not have an argument") %opt, opt)
opts.append(("--"+opt, optargor""))
returnopts, args


# Return:
# has_arg?
# full option name
deflong_has_args(opt, longopts):
possibilities= [oforoinlongoptsifo.startswith(opt)]
ifnotpossibilities:
raiseGetoptError(_("option --%s not recognized") %opt, opt)
# Is there an exact match?
ifoptinpossibilities:
returnFalse, opt
elifopt+"="inpossibilities:
returnTrue, opt
# No exact match, so better be unique.
iflen(possibilities) >1:
# XXX since possibilities contains all valid continuations, might be
# nice to work them into the error msg
raiseGetoptError(_("option --%s not a unique prefix") %opt, opt)
assertlen(possibilities) ==1
unique_match=possibilities[0]
has_arg=unique_match.endswith("=")
ifhas_arg:
unique_match=unique_match[:-1]
returnhas_arg, unique_match


defdo_shorts(opts, optstring, shortopts, args):
whileoptstring!="":
opt, optstring=optstring[0], optstring[1:]
ifshort_has_arg(opt, shortopts):
ifoptstring=="":
ifnotargs:
raiseGetoptError(_("option -%s requires argument") %opt, opt)
optstring, args=args[0], args[1:]
optarg, optstring=optstring, ""
else:
optarg=""
opts.append(("-"+opt, optarg))
returnopts, args


defshort_has_arg(opt, shortopts):
foriinrange(len(shortopts)):
ifopt==shortopts[i] !=":":
returnshortopts.startswith(":", i+1)
raiseGetoptError(_("option -%s not recognized") %opt, opt)


if__name__=="__main__":
importsys

print(getopt(sys.argv[1:], "a:b", ["alpha=", "beta"]))